The DXF file format, until recent revisions, does not include any reference to the unit and scale used in the drawing. Even in more recent versions, it is up to the user or to the CAD software to set those attributes.

HighDesign provides the DXF Import dialog to let you explicitly set those attributes before opening a file. Setting a wrong unit may affect dramatically the final result.

From the Drawing Units pop-up menu, select the unit you know or guess the drawing may use. It is important to choose the correct unit system: metric, inches or feet. Setting one instead of another can cause an incorrect scaling of the items and the drawing can be opened way too large or too small.

Once you have selected the unit, you can set the destination drawing scale. While this value does not usually cause problems, setting it very incorrectly (e.g. 1:2000 instead of 1:48) may cause a wrong scaling.
Often, when a drawing opens 'blank', it has most likely the wrong scale factor.

When opening a DXF 2000 or more recent version, HighDesign will try and set the unit as found inside the document if the "Set Units" checkbox is selected.
Uncheck it if you wish to set a different unit and have the program ignore any unit attribute.[/b]